/**
 * Copyright (c) 2010 Jesco Freund.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of Backtory nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id$
 */


#include "config.h"

#include <sys/types.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <unistd.h>

#include "backtoryd.h"
#include "backtory/error.h"
#include "message.h"

extern int
drop_privileges(msg_ctx_t *msgctx,  char *user, const char *group)
{
	int rval = 0;
	
	struct group grp;
	struct group *gptr;
	struct passwd pwd;
	struct passwd *pptr;
	char buf[1024];
	
	/* switch group */
	rval = getgrnam_r(group, &grp, buf, 1024, &gptr);
	if (rval)
		return rval;
	
	if (NULL == gptr)
		return E_BY_SYS_NOGROUP;

	if (0 > setgid(grp.gr_gid))
		return errno;
	else
		msg_log(msgctx, LOG_NOTICE, "Switched group context to %s\n", group);

	/* switch user */
	rval = getpwnam_r(user, &pwd, buf, 1024, &pptr);
	if (rval)
		return rval;
		
	if (NULL == pptr)
		return E_BY_SYS_NOUSER;
	
	if (0 > setuid(pwd.pw_uid))
		return errno;
	else
		msg_log(msgctx, LOG_NOTICE, "Switched user context to %s\n", user);
	
	return rval;
}
